My wife and I just booked a trip to Boston which has absolutely nothing to do with taking a cruise. But I used Expedia.com to buy the plane tickets and book the hotel. They have a very nice interface for sorting through the deals and finding exactly what you are looking for and they have some pretty good deals.
After I had made all the arrangements, I was just casually browsing around the website seeing what else they had to offer and making some mental notes for future potential trips and noticed that along the main menu bar across the top of the site that there is an option for cruises.
I spent long enough clicking around to notice that they have options for most of the major cruise lines and for destinations around the world. It really can’t get much easier to find the best deal than that.
With spring break rapidly approaching, now would be a great time to see what kind of last second deals are available as the cruise ships try to fill all their rooms.